[CMake] Wiki update needed: "CMake/Tutorials/How to create a ProjectConfig.cmake file"

[Johannes Zarl]

Hi,

I noticed that the tutorial for creating ProjectConfig files[1] in the wiki is 
not really up to date anymore. To be precise, the CMakePackageConfigHelpers 
cmake module is not mentioned on the page.

The main author of the tutorial goes by the username "Themiwi".

@Themiwi: if you are reading this: could drop me a quick note whether you have 
the time to update the wiki page or not?

Thanks,
  Johannes


[1] CMake/Tutorials/How to create a ProjectConfig.cmake file: 
http://www.cmake.org/Wiki/CMake/Tutorials/How_to_create_a_ProjectConfig.cmake_file